The present invention relates to a method and an upholstery cover for fabricating upholstered articles and in particular to a method which utilizes a pour-in-place process to mold a foam pad within an upholstery cover.
Many upholstered articles, such as seat cushions, seat backs and headrest pads for vehicle seat assemblies, are manufactured using a pour-in-place foam process. In such a process, an upholstery cover is first formed which defines a hollow interior space. This interior space is subsequently filled with a liquid foaming agent which cures to form a resilient foam pad that is at least partially covered by the upholstery cover. The pour-in-place process replaces a process in which a preformed and preshaped foam pad is mechanically attached or adhesively bonded to the cover member.
While the pour-in-place process has several advantages over using a preshaped foam pad such as a reduction in manufacturing steps, the pour-in-place process does present some difficulties of its own. For example, the liquid foam does not always force the upholstery cover outward against a mold surface or otherwise force the cover to the desired final shape.
Several methods have been developed for assisting in ensuring that the upholstery cover is in the proper position when filled with the foam. One method is disclosed in U.S. Pat. No. 4,987,666, assigned to the Assignee of the present invention. In the process disclosed in that patent, the seams of the cover are sewn with a stiff plastic welt to provide additional stiffness to the cover at the seams. This added stiffness helps to maintain the seams of the upholstery cover in the proper alignment. After the pour-in-place foaming operation, the external portion of the welt is removed. While the welts help to maintain proper alignment of the seams, there is limited interaction between the welts and the mold fixture to hold the welt against the mold surface. Incomplete filling of the upholstery cover can still result as there is no assurance that the welt will remain in contact with the surface of the foam molding fixture.
Accordingly, it is an object of the present invention to provide a method and apparatus for assuring that an upholstery cover is properly positioned with respect to a foam molding fixture.
The method of fabricating an upholstered product according to the present invention includes the following steps. First, an upholstery cover is provided having a hollow interior space and at least one positioning member extending from the cover. Second, the upholstery cover is mounted to a foam molding fixture. Third, the positioning member is secured to the foam molding fixture to retain a portion of the cover in a predetermined location relative to the foam molding fixture. Fourth, the hollow interior space of the cover is filled with a liquid foaming agent. Fifth, the positioning member is released from the foam molding fixture. Sixth, the filled cover is removed from the foam molding fixture and lastly, the extending portion of the positioning member is removed from the cover.
Various foam molding fixtures can be used with the above method depending upon the particular article being produced. Likewise, the extending positioning member can take a variety of forms.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.